1. Field of the Invention
This invention relates generally to a cannula guide device. More particularly, this invention relates to a cannula guide device that can securely and safely guide a cannula into a blood vessel or tract of a patient without accidental removal of its already pricked guide needle from the patient's blood vessel or tract, or without undue damage to the patient's blood vessel or tract or skin by the guide needle, or without undue pains to the patient.
2. Prior Art
It is generally time consuming to perform blood transfusion or fluid transfusion on a patient. Before, a patient was required to undergo a long and often painful fluid transfusion treatment with a conventional injection needle to be inserted into his or her blood vessel or tract. The patient had to stay substantially motionless during the long transfusion treatment in order to prevent the injection needle from accidentally coming off his or her blood vessel or tract. If the injection needle accidentally comes off, the injection needle must be pricked into the patient again. The patient's awkward movement might additionally cause damage onto his or her blood vessel or tract or even skin with the sharp needle end, which would inevitably accompany considerable pains to be suffered by the patient.
Cannula guide devices have been introduced in replacement of such conventional injection needle devices so as to perform safer and securer and thus less painful fluid transfusion on a patient who needs transfusion treatment, to a great benefit not only to the patient but also to the medical personnel who performs the transfusion treatment upon the patent.
A conventional cannula guide device is comprised of a needle holder, a cannula and a guide needle axially secured to the needle holder. The guide needle is provided through the fluid passage of the cannula with its forward or distal end protruding a few millimeters from the distal end of the cannula so as to be pricked ahead of the cannula into a patient's blood vessel or tract hypodermically. The cannula is then pushed or pulled and slid forward or distally on the axially provided internal guide needle into the blood vessel or tract. When the distal end of the cannula is pricked or inserted into the blood vessel or tract, the guide needle is pulled rearward or proximally and removed from the blood vessel or tract and eventually from the cannula entirely in order to clear the fluid passage of the cannula for transfusion treatment. Blood or fluid is then pumped into or extracted from the blood vessel or tract through the fluid passage of the cannula.
Such a conventional cannula guide device provides an invaluable benefit to patients who need transfusion treatment as well as medical personnel who perform transfusion on such patients, but not without a serious shortcoming. The shortcoming that inevitably accompanies conventional cannula guide devices is described hereinunder using the accompanying FIG. 5 (prior art), in which a cannula guide device 80 is shown comprising a cannula 61, a guide needle 71, a cannula base 70b, and a needle holder 70a. The guide needle 71 is provided through the fluid passage (not shown) formed through the cannula 61. The rear or proximal end of the cannula 61 is secured to the forward or distal end of the cannula base 70b.
After the guide needle 71 is pricked into a blood vessel or tract 90 of a patient (not shown) a couple of millimeters deep, the cannula guide device 80 is generally held with four fingers as shown in FIG. 5. The cannula base 70b is held between a thumb and index finger of one hand, while the needle holder 70a is held between the other thumb and index finger. The cannula 61 is pushed (or pulled) forward or distally in the direction shown by an arrow F1 to be inserted into the blood vessel or tract 90 where the guide needle 71 has been pricked, while the needle holder 70a is carefully held still. Otherwise, the needle holder 70a may be inadvertently pulled rearward or proximally in the direction shown by an arrow F2 as a reaction, which would pull the pricked guide needle 71 inadvertently out of the blood vessel or tract 90, and may cause damage on the blood vessel or tract 90 or the patient's skin. Such can likely happen when the medical performer is pressed for time. The guide needle 71 must be pricked into the blood vessel or tract 90 over again, to the physical as well as mental detriment of the patient, which would be equally detrimental to the medical performer.